"My favorite NBA player, Blake Griffin, was int it, so I thought it would be a cool thing to do," Rob says about taking it all off for the mag. "This issue shows just how hard athletes work. We're working out all the time, making sure we're staying in shape, making sure we're strong and fast."

As a special sneak peek at the issue -- on newsstands Friday -- we've also got very revealing shots of New York Knicks' Tyson Chandler, WNBA player Candace Parker and the U.S. Olympic Women's Volleyball team.